1. Field of the Invention
The present invention relates to a grinding table apparatus for a liquid crystal display panel and a grinder apparatus using the same, and more particularly, to a grinding table apparatus for a liquid crystal display panel and a grinder apparatus using the same capable of adapting to various sizes of unit liquid crystal display panels for grinding edges of the unit liquid crystal display panels that result from cutting liquid crystal display panels fabricated on a large-sized mother substrate into the unit liquid crystal display panels.
2. Discussion of the Related Art
Generally, a liquid crystal display (LCD) panel is cut into a plurality of unit LCD panels to improve yield. For simultaneously producing LCD panels, a plurality of thin film transistors and color filters are formed on two different mother substrates, respectively. Thereafter, the two mother substrates are attached to each other.
Conventionally, cutting of the unit LCD panel is performed through the process of forming a scribing line on the surface of the mother substrate with a wheel having a hardness higher than glass and then breaking the mother substrate along the scribing line. The process for fabricating an LCD apparatus will be described with reference to the accompanied drawings.
FIG. 1 is a schematic cross-sectional view illustrating a first mother substrate including thin film transistor array substrates and a second mother substrate including color filter substrates. The first and second mother substrates are attached to each other, thereby forming a plurality of unit LCD panels.
With reference to FIG. 1, the unit LCD panels are formed so that one side of thin film transistor array substrate 1 extends beyond color filter substrate 2. This is because a gate pad unit (not shown) and a data pad unit (not shown) are formed in the margin area of the thin film transistor array substrates 1 that do not overlap the color filter substrates 2.
Therefore, the color filter substrates 2 formed on the second mother substrate 30 are spaced apart to allow for a dummy region 31 corresponding to the region where the thin film transistor array substrates 1 extend on the first mother substrate 20.
Also, the respective unit LCD panels are positioned to effectively utilize the first and second mother substrates 20 and 30. The area by which the unit LCD panels are spaced apart to allow for the dummy region 32 depends on the model of the liquid crystal display panel being produced.
The first mother substrate 20 where the thin film transistor array substrates 1 are included, and the second mother substrate 30 where the color filter substrates 2 are included, are attached to each other. Thereafter, the LCD panels are cut into individual panels. The dummy region 31, where the color filter substrates 2 of the second mother substrate 30 are formed, and the dummy region 32 for separating the unit LCD panels are simultaneously removed at this time.
After cutting the second mother substrate 30 into the unit LCD panels, a shorting line formed at the marginal portion of the thin film transistor array substrate 1 for intercepting static electricity is removed. In this process, a sharp corner of the unit LCD panel is ground. Static electricity may occur at the shorting line when a conductive film is formed on the thin film transistor array substrate 1. Also, by grinding the sharp corner of the LCD panel, pieces are not separated from the corner of the unit LCD panel by the external impact. Grinding also prevents an operator from being injured by the sharp corner of the unit LCD panel in the fabrication process.
FIG. 2 is a schematic plan view of the conventional unit LCD panel.
With reference to FIG. 2, a unit LCD panel 10 includes a picture display unit 13 in which liquid crystal cells are arranged in a matrix form, a gate pad unit 14 for connecting a plurality of gate lines GL1 to GLm of the picture display unit 13 to a gate driver integrated circuit (not shown), to which a gate signal is applied, and a data pad unit 15 for connecting a plurality of data lines DL1 to DLn of the picture display unit 13 to a data driver integrated circuit (not shown), to which the picture information is applied. The gate pad unit 14 and the data pad unit 15 are formed at the marginal portion of the thin film transistor array substrate 1 where both side edges extend relative to the color filter substrate 2.
At the region where the data lines DL1 to DLn and the gate lines GL1 to GLm vertically cross one another, a thin film transistor (not shown) for switching the liquid crystal cell is formed therein. A pixel electrode is formed to be connected to the thin film transistor for driving the liquid crystal cell. A passivation film (not shown) is formed on the entire surface to protect the data lines DL1 to DLn, the gate lines GL1 to GLm, the thin film transistors, and the electrodes.
Also, a shorting line (not shown) for electrically shorting out the conductive films is formed at the marginal portion of the thin film transistor array substrate 1, to remove static electricity which may be generated during formation of the data lines DL1 to DLn, the gate lines GL1 to GLm, and the various electrodes on the thin film transistor array substrate 1.
At the color filter substrate 2 of the picture display unit 13, a plurality of color filters (not shown) are coated and separated by cell regions with a black matrix. A common transparent electrode (not shown) corresponding to the pixel electrode is formed at the thin film transistor array substrate 1.
A cell gap (not shown) is formed between the thin film transistor array substrate 1 and the color filter substrate 2 so that the two substrates are spaced apart and face each other. The thin film transistor array substrate 1 and the color filter substrate 2 are attached by a seal (not shown) formed at the exterior of the picture display unit, 13. A liquid crystal layer (not shown) is formed between the thin film transistor array substrate 1 and the color filter substrate 2.
A grinder apparatus for grinding each of the individually cut unit liquid crystal display panels 10 is explained in detail by referring to the attached drawing as follows.
FIG. 3 illustrates an exemplary diagram of a grinding table apparatus for a unit liquid crystal display panel and a grinder apparatus using the same according to a related art.
Referring to FIG. 3, a grinder apparatus according to a related art includes a loading unit 50 loading a cut unit liquid crystal display panel 10 thereon, a grinding unit 53 receiving the unit liquid crystal display panel 10 loaded on the loading unit 50 so as to arrange the received unit liquid crystal display panel 10 on a grinding table 51 and for grinding edges of the unit liquid crystal display panel 10 through a grind wheel 52 rotating at high speed, and an unloading unit 54 receiving the grinded unit liquid crystal display panel 10 from the grinding unit 53 so as to unload the received panel 10.
The grinding table 51 should be designed to have a size smaller than that of the unit liquid crystal display panel 10 to grind the edges of the unit liquid crystal display panel 10 obliquely as well as support the unit liquid crystal display panel 10 effectively. Compared to the edges of the grinding table 51, the edges of the unit liquid crystal display panel 10 extend beyond those of the grinding table 51.
FIGS. 4A to 4C illustrate exemplary diagrams of grinding tables in accordance with a variable size of a unit liquid crystal display panel according to a related art.
Referring to FIG. 4A, a grinding table 60 has a size somewhat smaller than that of a unit liquid crystal display panel 10 so that edges of the unit liquid crystal display panel 10 protrude slightly.
However, referring to FIGS. 4B and 4C, when sizes of unit liquid crystal display panels 70 and 80 are greater than that of the unit liquid crystal display panel 10 in FIG. 4A, the grinding table 60 in FIG. 4A fails to support the unit liquid crystal display panel 70 stably. On the contrary, when the size of the unit liquid crystal display panel 80 is smaller than that in FIG. 4A, edges of the liquid crystal display panel 80 do not protrude sufficiently from those of the grinding table 60 in FIG. 4A to allow for proper grinding.
In order to grind the unit liquid crystal display panel 70 in FIG. 4B, the grinding table 60 in FIG. 4A is removed from a production line and a large-sized grinding table 71 is installed at the production line. Likewise, in order to grind the unit liquid crystal display panel 80 in FIG. 4C, the grinding table 60 in FIG. 4A is removed from the production line to install a new grinding table 81 having a smaller size at the production line again.
Unfortunately, the grinding table according to the related art involves a tedious job of replacing the previously used grinding table with the new grinding table having a size corresponding to that of a liquid crystal display panel when the size of the liquid crystal display panel is changed. Such process reduces productivity due to a delayed process time.
Moreover, according to the related art, a plurality of grinding tables must be prepared to correspond to various sizes of liquid crystal display panels, thereby increasing its production cost, as well as requiring extra space to store the plurality of the grinding tables.